JPH0627800A - Developing apparatus of electrophotographic recording device - Google Patents

Abstract

PURPOSE:To lengthen the life of a developing apparatus and hold an excellent image for a long period by performing the prevention of toner fixing to a blade for thinning a toner layer. CONSTITUTION:When the number of copies counted by a copy counter reaches an assigned number, an input signal is sent to a CPU. As an output port, a drive motor for a developing roller 15+ a photoreceptor body is set to off at first, and then a lift 19 for cleaning a blade 17, for thinning a toner layer, is set to on. When the down movement of the lift 19 starts, the blade 17 for thinning the toner layer can be alienated, as an alienation path is controlled by an alienation path guide member 22 attached thereto, so as not to scratch the developing roller 15. During the alienation movement the toner fixed to the surface thereof is scraped off by a cleaning member 18.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing device for an electrophotographic recording apparatus, and more particularly to a developing device using a triboelectrification type developing device to prevent toner sticking of a toner thinning blade. For example, it is applied to a facsimile, a printer, a copying machine and the like.

[0002]

2. Description of the Related Art Known documents describing the prior art of the present invention include, for example, Japanese Utility Model Laid-Open No. 3-84851 and Japanese Utility Model Laid-Open No. 3-80448. Actual Kaihei 3-8485
The "developing device for electrophotographic apparatus" of Japanese Patent Laid-Open No. 1-301 is for directly contacting a developing roller with a heat-conducting member having a high thermal conductivity to prevent the surface strength of the developing roller from being raised by frictional heat. In addition, "Development device" of Japanese Utility Model Laid-Open No. 3-80448
Is fixed to the main body of the apparatus such that the developer layer thickness regulating member comes into contact with and separates from the developer carrying member without hindering the movement for the attachment and detachment of the developing device according to the attachment and detachment of the developing device. Positioning means for regulating the relative position of the developer carrying member and the developer layer regulating member are provided.

Generally, an electrophotographic recording apparatus forms an electrostatic latent image by precharging a photosensitive belt and then performing optical writing. Toner is applied to the electrostatic latent image to develop the latent image, and then the toner image is transferred to a separately supplied recording paper.
The recording paper on which the toner image is transferred is heated, fixed, and discharged. On the other hand, the toner remaining on the photoconductor is scraped off by a cleaning blade and collected as waste toner, and the residual charge is discharged by irradiating light. As a developing device used in such an electrophotographic recording apparatus, a triboelectric charging method is used when the cost is relatively low. As an example,
μ-ISP development is fried. In the μ-ISP development, a developing roller (magnet roller) and a magnetic toner thinning blade having thin elasticity, which is provided in a tangential direction to the developing roller, are attracted to the roller surface by the magnetic force of the developing roller, and the pressure and the blade are applied. A single layer of toner is applied onto the roller by the balance of the force of the toner pushed into the protruding portion to push up the blade, and at this time, the toner is charged with a charge by friction with the roller. The toner used is a component.

The above-mentioned frictional charging type developing device (μ-IS
In P), the problem is toner sticking at the contact portion between the toner thinning blade and the developing roller. This is remarkable when the toner is continuously slid on the toner layer thinning blade without the toner flying from the developing roller to the photosensitive member. As a result of the toner sticking, vertical streak-shaped black stripes are generated in the image. Black streaks appearing on the image cannot be erased unless the toner adhesion of the toner thinning blade is wiped off. Examples of obstacles are as follows. When a manuscript close to pure white (written with a few lines) is read and the image forming operation is repeated, a black streak appears on the image after several hundred sheets. When the developing roller has a width of B4 and several hundreds of sheets are used for A4 size image formation and the mode is changed to B4 size image formation operation, the toner thinning blades other than the A4 size part are stuck. Then, a black streak occurs in the image corresponding to that portion. In order to remove the black streaks on these images, a service person must clean the toner thinning blade.

[0005]

[Object] The present invention has been made in view of the above circumstances, and it is possible to automatically prevent toner sticking of a toner thinning blade, prolong the life of a developing device, and retain a good image for a long period of time. The purpose of the present invention is to provide a developing device for an electrophotographic recording device.

[0006]

In order to achieve the above object, the present invention provides (1)
In a developing device of an electrophotographic recording device, which makes a toner thinning blade frictionally contact a developing roller, presses the developing roller against a photoconductor to attach toner, and visualizes a latent image on the surface of the photoconductor Providing a copy counter for counting the number of copies, separating the toner thinning blade from the developing roller when a certain number of copies is reached, and cleaning the toner thinning blade with a cleaning member, Alternatively,
(2) An electrophotographic recording apparatus for bringing a toner thin layer blade into frictional contact with a developing roller, pressing the developing roller against a photoconductor to attach toner, and visualizing a latent image on the surface of the photoconductor. In the developing device, a paper discharge sensor is provided, and after the copying operation is completed, the toner thinning blade is separated from the developing roller and the toner thinning blade is cleaned by a cleaning member, or (3) toner thinning In the developing device of the electrophotographic recording apparatus, the layering blade is brought into frictional contact with the developing roller, the developing roller is pressed against the photoconductor to adhere the toner, and the latent image on the surface of the photoconductor is visualized. The stirring agitator is provided with a torque limiter, and when the toner end is detected, the toner thinning blade is separated from the developing roller, and the cleaning member cleans the toner thinning blade. It is. Hereinafter, description will be given based on examples of the present invention.

First, the electrophotographic recording apparatus will be described with reference to FIG. In the figure, 1 is a photoconductor, 2 is a precharger, 3 is an exposure unit, 4 is a developing unit, 5 is a transfer unit, 6 is a fixing unit, 7 is a static eliminator, 8 is a CTM, 9 is a toner replenishing tank unit, 10 Is a spiral, 11 is a drop duct, 12 is a waste toner recovery tank part, 13 is a cleaning blade holder, 14 is a cleaning blade, 15 is a developing roller,
Reference numeral 16 is an agitator (for stirring toner), and 17 is a toner thinning blade. A process unit including a photoconductor 1, a precharger 2, an exposure unit 3, a developing unit 4, a transfer unit 5, a fixing unit 6 and a static eliminator 7, and a CTM 8 as a cleaning unit and a toner replenishing unit are provided. Replenishment of toner to the developing device 4 is performed through the drop duct 11 by the spiral 10 inside the toner replenishment. A sheet metal holder 13 was held in the waste toner recovery tank section 12 of the CTM 8 in which the waste toner recovery tank section 12 and the toner replenishment tank section 9 were integrally formed and were replaceably arranged in front of the static eliminator 7. There is a cleaning blade 14, and the untransferred toner on the photoconductor 1 is scraped off by the cleaning blade 14 and is stored in the waste toner recovery tank section 12.

FIGS. 5 (a) and 5 (b) are views showing a cleaning state of the toner layer thinning blade of the developing device. FIG. 5 (a) is a stationary state, and FIG. 5 (b) is a cleaning state of separating the toner layer thinning blade. Each state is shown. In the figure, 18 is a cleaning member, 19 is an elevator, 20 is an elevator drive motor, 21 is a wire, 22 is a separating path guide member, and other parts having the same operation as in FIG. The CPU sends a signal notifying the cleaning time of the toner thinning blade, the developing roller + photosensitive member drive motor is turned off, the elevator drive motor 20 is turned on, and the elevator 19 starts the descending operation. The toner thinning blade 17 can be separated so as not to damage the developing roller 15 while controlling the separation path by the separation path guide member 22 attached thereto, and adhered to the surface by the cleaning member 18 during the separation operation. Toner is scraped off.

FIG. 1 is a view for explaining an embodiment (claim 1) of the developing device according to the present invention. In the drawing, 31 is a copy counter, 32 is a toner thinning blade lifting motor O.
N / OFF trigger, 33 is a developing roller + photoconductor drive motor ON / OFF trigger, and 34 is a CPU (central processing unit)
Is. When the number of copies counted by the copy counter 31 reaches the specified number, an input signal is sent to the CPU 34. As the output port, first, the developing roller + photosensitive member drive motor is turned off, and the elevator for cleaning the toner thinning blade is turned on. The operation at the time of cleaning is as described above.

FIG. 2 is a view showing another embodiment (claim 2) of the developing device according to the present invention. In the drawing, 35 is a paper discharge sensor, and the other parts which have the same function as FIG. 1 are the same. The symbol is attached. When the end of the copying operation is detected by the paper discharge sensor attached to the side of the fixing device 6 opposite to the photoconductor 1, C
Send an input signal to PU. The output port is the same as described above.

FIG. 3 is a view showing still another embodiment (claim 3) of the developing device according to the present invention, in which 36 is an agitator / torque limiter for agitating the toner in the developing device, and FIG. Portions having the same function are designated by the same reference numerals. When the torque limiter 36 is attached to the toner stirring agitator 16 inside the developing device 4 and the toner END is detected,
Send an input signal to the CPU. The output port is the same as described above.

[0012]

As is apparent from the above description, the present invention has the following effects. (1) Effect corresponding to claim 1: The toner thinning blade has a different fixing time depending on the toner type. By registering in advance the number of sheets to notify the cleaning time to the copy counter so that the blade can be cleaned before it sticks, the blade can be cleaned efficiently, so that the life of the developing device is extended and a good image is obtained. Can be held for a long time. (2) Effect corresponding to claim 2: Due to cost reduction,
There are many cases where the toner is changed for running. In such a case, naturally, the toner fixing time also changes. To deal with such a situation, the toner thinning blade is cleaned after one copy. Therefore, in the present invention, by including a step of cleaning the toner thinning blade after one copy, maintenance of the developing device can be eliminated and a good image can be held for a long time. With this method, the continuous copying time becomes long, so that the effect is exerted in a facsimile or the like that does not perform continuous copying very much. (3) Effect corresponding to claim 3: When the step of cleaning the toner thinning blade is incorporated, the operation time of the machine becomes longer accordingly. In today's demand for high-speed machine expansion, it is necessary to reduce operating time. Do this cleaning when the machine called Toner END stops,
The mechanical operation can be shortened, maintenance of the developing device can be eliminated, and good images can be retained for a long time even if continuous copying is performed.

[Brief description of drawings]

FIG. 1 is a configuration diagram for explaining an embodiment of a developing device of an electrophotographic recording apparatus according to the present invention.

FIG. 2 is a diagram showing another embodiment of the developing device of the electrophotographic recording apparatus according to the present invention.

FIG. 3 is a view showing still another embodiment of the developing device of the electrophotographic recording apparatus according to the present invention.

FIG. 4 is a configuration diagram of an electrophotographic recording apparatus according to the present invention.

FIG. 5 is a diagram showing a cleaning state of a toner thin layer blade of the developing device according to the present invention.

[Explanation of symbols]

18 ... Cleaning member, 19 ... Elevator, 20 ... Elevator drive motor, 21 ... Wire, 22 ... Separation path guide member, 31 ... Copy counter, 32 ... Toner thinning blade elevating motor O
N / OFF trigger, 33 ... Developing roller + photoconductor drive motor ON / OFF trigger, 34 ... CPU (central processing unit).

Claims (3)

[Claims] 1. An electrophotographic recording in which a toner thinning blade is brought into frictional contact with a developing roller, and the developing roller is pressed against a photosensitive member to adhere toner, thereby making a latent image on the surface of the photosensitive member visible. In the developing device of the apparatus, a copy counter for counting the number of copies is provided, and when the predetermined number of copies is reached, the toner thinning blade is separated from the developing roller, and the toner thinning blade is removed by the cleaning member. A developing device for an electrophotographic recording apparatus, which is characterized by cleaning. 2. An electrophotographic recording in which a toner thinning blade is brought into frictional contact with a developing roller, and the developing roller is pressed against a photosensitive member to adhere toner to make a latent image on the surface of the photosensitive member visible. In the developing device of the apparatus, a paper discharge sensor is provided, the toner thinning blade is separated from the developing roller after the copying operation is completed, and the toner thinning blade is cleaned by a cleaning member. Developing device of recording device. 3. An electrophotographic recording in which a toner thinning blade is brought into frictional contact with a developing roller, and the developing roller is pressed against a photosensitive member to adhere toner to make a latent image on the surface of the photosensitive member visible. In the developing unit of the apparatus, a torque limiter is provided in the toner agitator, and when the toner end is detected, the toner thinning blade is separated from the developing roller, and the cleaning member cleans the toner thinning blade. The developing device of the characteristic electrophotographic recording device.